A cellular radio access network is a collection of cells that each includes at least one base station capable of transmitting and relaying signals to subscribers' wireless devices. A “cell” generally denotes a distinct area of a mobile network that utilizes a particular frequency or range of frequencies for transmission of data. A typical base station is a tower to which are affixed a number of antennas that transmit and receive the data over the particular frequency. Wireless devices, such as cellular or mobile phones, smart phones, camera phones, personal digital assistants (PDAs) and laptop computers, may initiate or otherwise transmit a signal at the designated frequency to the base station to initiate a call or data session and begin transmitting data.
Mobile service provider networks convert cellular signals, e.g., Time Division Multiple Access (TDMA) signals, Orthogonal Frequency-Division Multiplexing (OFDM) signals or Code Division Multiple Access (CDMA) signals, received at a base station from wireless devices into Internet protocol (IP) packets for transmission within packet-based networks. A number of standards have been proposed to facilitate this conversion and transmission of cellular signals to IP packets, such as a general packet radio service (GPRS) standardized by the Global System for Mobile Communications (GSM) Association, a Universal Mobile Telecommunications System (UMTS), an evolution of UMTS referred to as Long Term Evolution (LTE), as well as other standards proposed by the 3rd Generation Partnership Project (3GPP), 3rd Generation Partnership Project 2 (3GGP/2) and the Worldwide Interoperability for Microwave Access (WiMAX) forum.
A typical 3GPP mobile service provider network, or mobile network, includes a core packet-switched network, a transport network, and one or more radio access networks (RANs). The core packet-switched network for the mobile network establishes logical connections, known as bearers, among the many service nodes on a path between a wireless device, attached to one of the radio access networks, and a packet data network (PDN). The service nodes then utilize the bearers to transport subscriber traffic exchanged between the wireless device and the PDN, which may include, for example, the Internet, an enterprise intranet, a layer 3 VPN, and a service provider's private network. Various PDNs provide a variety of packet-based data services to wireless devices to enable the wireless devices to exchange service data with application or other servers of the PDNs.
In forming these bearers, the service nodes may establish a tunnel to support the bearers. In order to establish these tunnels, one service node acting as an endpoint for each tunnel may signal a tunnel endpoint identifier (TEID) instructing the other service node acting as the other endpoint of the tunnel to be established of the TEID to use when sending subscriber traffic via this tunnel. The receiving endpoint service node may then associate the signal TEID with the subscriber device (often, by associating the TEID with an Internet Protocol (IP) address assigned to the subscriber device in what is commonly referred to as a subscriber record). A service node may, however, not receive this TEID or otherwise associate this TEID with the corresponding subscriber device for any number of reasons (including dropping the packet signaling this TEID, a failure of the receiving endpoint service node, etc.).
If the association is not established, this endpoint subscriber device, upon receiving a packet sent through this tunnel having the unknown (at least from the perspective of the receiving endpoint service node for which no association is maintained) TEID, may issue an error indication packet to the service node that sent the packet having this unknown TEID identifying the received TEID as unknown (meaning that the service node that received the packet having this TEID has not associated this with a subscriber device). In response to receiving this error indication packet, the sending service node may perform a linear scan of subscriber records to determine to which subscriber device this TEID is associated. In large scale mobile networks having hundreds of thousands or even a million or more subscribers, the service node may be required to assess potentially hundreds of thousands or even a million or more subscriber records to identify to which subscriber the TEID specified in the error indication packet is associated. Consequently, handling of such error indication packets identifying unknown TEIDs may be time-consuming and require significant resources in terms of processor cycles and memory, which may delay delivery of subscriber traffic and otherwise impact the user experience associated with providing data services via the mobile network.